<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    #d1{
      width: 100px;
      height: 100px;
      border: 1px solid red;
      /*单独某个方向添加外边距*/
      margin-top: 100px;
      margin-left: 50px;
      margin-bottom: 50px;
      margin-right: 50px;
      /*四个方向添加*/
      margin: 50px;
      /*上下和左右赋值*/
      margin: 50px  100px;

      /*居中写法*/
      margin: 0 auto;
      /*上右下左 顺时针赋值*/
      margin: 10px 20px  30px  40px;
    }
    #d2{
      width: 100px;
      height: 100px;
      border:1px solid blue;
      /*上下相邻彼此添加外边距,去最大值*/
      margin-top: 50px;
    }
    /*行内元素上下外边距无效*/
    #s1{
      margin-left: 50px;
    }
    /*左右相邻彼此添加外边距，两者相加*/
    #s2{
      margin-left: 50px;
    }

    #big {
      width: 200px;
      height: 200px;
      background-color: green;
        overflow: hidden;
    }

      #big>div{
        width: 50px;
        height: 50px;
        background-color: purple;
        margin-left: 50px;
        margin-top: 50px;
        /*当元素的上边缘和上级元素 边缘重叠时，给元素添加上外边距会出现粘连问题，会给上级元素添加overfiow:hidden样式解决*/


      }

  </style>
</head>
<body>
<div id="big">
  <div></div>
</div>
<span id="s1">span1</span>
<span id="s2">span2</span>
<div id="d1"></div>
<div id="d2"></div>

</body>
</html>